A cyclone dust separating apparatus separates dust from dust laden air using centrifugal force. Cleaned air is discharged while the dust separated is collected in a dust collecting chamber. Cyclone dust separating devices are used in vacuum cleaners because they can be used permanently (unlike a dust bag, which requires replacement when it becomes full).
One problem with cyclone dust separators is their relative inability to separate out fine dust particles. To overcome this limitation, so-called multi-cyclone dust separating devices have been suggested in order to improve dust separation efficiency. The multi-cyclone dust separating apparatus includes a first cyclone chamber and a plurality of secondary cyclone chambers which are arranged in series or parallel. Relatively large dust particles are separated out in the first or primary cyclone; smaller dust particles are separated out in the second or secondary cyclones.
Although multi-cyclone dust separating devices provide better dirt particle separation than conventional cyclone dust separating devices, their ability to separate out minute dirt particles is compromised by the geometry required to route dust laden air through a primary cyclone and then into one or more secondary cyclones.
The suction force in a multi-cyclone dust separator is typically obtained from a suction force source applied to the multi-cyclone separator at a lower portion of the multi-cyclone dust separating apparatus. The vacuum source must draw dust laden air through a multi-cyclone dust separating apparatus after it has drawn the dust laden air through one or more secondary cyclones, which receive air from a primary cyclone. Extending a vacuum through a multi-cyclone dust separating apparatus from the dirt laden air intake to the filtered air outlet usually requires at least one extra duct to connect the cyclones of different stages to each other. Among other things, extra ducting makes the structure of the multi-cyclone dust separating apparatus big and complicated. In addition, additional ducting reduces suction force because of head losses attributable to an increased air path length.
Another problem resulting from prior multi-cyclone dust separating devices is the single dirt collecting unit, into which the various cyclones dump the centrifuged dirt and dust particles. A user cannot empty individual dirt collecting chambers. Rather, the user is required to empty the entire chamber. Since the dust-collecting chambers are not separable from each other, it is sometimes inconvenient to clean or repair a single dust-collecting chamber.